Search PubMed⌕ Search

Biomedical subjects

P Malet

Publications and source records attributed to P Malet.

At least 37 records · Page 2Linked to original sources

A history of miscarriages and mild prognathism as possible mode of presentation of mosaic trisomy 18 in women.

A 22-year-old woman seeking medical assistance for hypofertility after two miscarriages had very slight anomalies: mild macrogenia and prognathism, and temporal depilation. Peripheral lymphocytes and fibroblastic karyotypes disclosed the tenth published case of low-level mosaicism for trisomy 18 with normal intelligence. Subfertility is frequently observed among these patients. As women with this anomaly are at risk of trisomy 18 pregnancies and as five cases have been reported recently, this particular chromosomal anomaly may not be so exceptional and should be investigated in cases of hypofertility.

Abortion, Habitual↗

Prenatal diagnosis of trisomy 21 using interphase fluorescence in situ hybridization of post-replicated cells with site-specific cosmid and cosmid contig probes.

Interphase fluorescence in situ hybridization (FISH) with chromosome 21-specific cosmid clones was used to identify trisomy 21 in cultured and uncultured amniotic cells. Two novel site-specific cosmid clones (regions 21q22 and 21qtel) were compared with a cosmid contig (Zheng et al., 1992). Correct identification of chromosome 21 copy number was made in 65-75 per cent of trisomic cells and in 70-75 per cent of normal disomic cells by using all the tested probes. However, the chromosome 21-specific telomeric probe (cos 17F8) showed the best results due to more intense and clearly visible hybridization. Utilization of a directly fluorophorated telomeric probe using Cy3-dCTP and FluorX-dCTP allows accurate detection of chromosome 21 in a fast 'one-step' FISH procedure on uncultured interphase nuclei. In addition, we compared the efficacy of FISH analysis for the total population of interphase cells and cells in the post-replication (late S, G2) periods of the cell cycle. Selective scoring of cells in the post-replicative period (showing a pair of hybridization signals on each chromatid of the replicated interphase chromosome) increased the number of informative nuclei by up to 95-97 per cent. This approach allows cells with overlapping chromosomes, artificial double hybridization signals on separate chromatids in interphase chromosomes, background hybridization, and polyploid cells to be analysed. Application of directly labelled telomeric cosmid probes and integral analysis of hybridized nuclei in the pre- and post-replication periods of the cell cycle may help to further improve the prenatal detection of trisomy 21.

Amniotic Fluid↗

Rehybridization on metaphases studied previously by FISH. An approach to analyze chromosome aberrations.

A new protocol for fluorescence in situ rehybridization is described. Biotin-labeled chromosome-specific DNA probes were hybridized onto metaphases which previously had been studied by FISH. This method makes it possible to reexamine the same metaphase spreads with different DNA probes. It allows for precise characterization of cytogenetic translocations and for detection of multiple aberrations presented in a karyotype. It is especially useful in cases where a limited number of cytogenetic preparations are available.

Chromosome Aberrations↗

Cytogenetic and molecular findings in patients with Turner's syndrome stigmata.

Cytogenetic and DNA analysis in 12 people with stigmata of Turner's syndrome was carried out. Cytogenetic analysis of these patients showed two subjects with 46,X, i(Xq) karyotypes, one with 45,X/46,X, i(Xq), one with 46,X,t(X;Y), and eight with 45,X/46,X,mar. Molecular analysis of DNA samples was performed in nine out of 12 patients with marker chromosomes. PCR analysis with oligoprimers specific for SRY, DYZ1, or DYZ3 loci identified Y chromosome material in five patients in the latter group. The X chromosome origin of the marker chromosome was proved by FISH technique with biotin labelled pericentromeric X chromosome specific probe in four other patients. These results show that patients with a number of Turner's syndrome stigmata usually do not have a typical XO karyotype but have some structural chromosomal aberrations involving the X or Y chromosomes. Combined application of cytogenetic, molecular cytogenetic (FISH), and PCR techniques significantly improves the precision of marker chromosome identification and thus might be of practical importance for the proper management and treatment of affected patients. Peculiarities of pathological manifestations of different karyotypes bearing structural abnormalities of the X or Y chromosomes in patients with Turner's syndrome stigmata, as well as feasible genetic mechanisms of sex determination and differentiation abnormalities in these subjects, are briefly discussed.

Adolescent↗

Simultaneous in situ hybridization with biotin-labeled centromeric and library DNA probes: a useful method for identifying translocations.

A method of in situ hybridization is described for rapid characterization of cytogenetical translocations. In the same experimental procedure, biotinylated centromeric and 'painting' DNA probes were used in combination. Signals of the double-target hybridization were visualized by only one fluorescein. This technique also permits a simultaneous detection of multiple unrelated aberrations involving several chromosomes.

Biotin↗

Hepatic calcifications in a fetus with trisomy 9 that underwent cordocentesis.

Foci of calcification were observed at autopsy in the liver of a fetus with complete trisomy 9 on which two cordocenteses had been performed. It is suggested that liver calcifications are a possible complication of the procedure. As several other cases of calcifications in the liver and other organs of fetuses with autosomal trisomies have been described without a history of cordocentesis, further studies should be carried out to determine whether fetuses with chromosomal anomalies are more prone to thrombus formation and embolization.

Adult↗

Nonrandom changes of chromosome 10 in bladder cancer. Detection by FISH to interphase nuclei.

Fluorescence in situ hybridization (FISH) to interphase nuclei has been a valuable method for examining the chromosome copies in tumor cells in clinical practice. Twelve cases of transitional cell carcinoma (TCC) of the bladder were investigated with a biotin-labeled repetitive DNA probe to detect numerical aberrations of chromosome 10 in interphase nuclei. The cells containing one fluorescent signal were screened in two of seven non-invasive tumors and in four of five invasive tumors. Two patients presented two FISH spots of different sizes. More than two signals were seen in one invasive tumor. The findings suggest that partial or complete loss of a chromosome 10 is a nonrandom aberration in bladder cancer.

Carcinoma, Transitional Cell↗

X;Y translocation in a girl with short stature and some features of Turner's syndrome: cytogenetic and molecular studies.

A 13 year old girl referred for chromosome analysis because of disproportionate short stature (short neck, curved legs, pectus excavatum) with an initial clinical diagnosis of Turner's syndrome was found to have the karyotype 46,X, + der(X) in 100% of her blood lymphocytes. By means of conventional differential staining (QFH/AcD, FPG, and RBA banding) supplemented with distamycin A treatment, the karyotype of the proband was interpreted as 46,X,t(X;Y) (p22.3;q11). The rearranged marker X chromosome was found to be active in 91% of lymphocytes studied. PCR analysis with Y chromosome specific oligoprimers showed the presence of some Y chromosome long arm DNA in both lymphocyte and gonadal tissue biopsy cells. At laparoscopy the patient was found to have small gonads with a rudimentary uterus and fallopian tubes. Histological examination of gonadal tissue showed primary follicles with dystrophic changes of the germ cells and numerous follicular cysts (polycystic ovaries). The proband's phenotype and its correlation with the genetic imbalance of the rearranged X chromosomes, as well as with non-random t(X;Y) chromosome inactivation, are briefly discussed.

Child↗

Interphase cytogenetic studies of bladder cancer.

Transitional cell carcinomas of human urinary bladder were studied by interphase fluorescence in situ hybridization (FISH). With current hybridization to isolated nuclei, 26 tumors were investigated and nonrandom +7, -9 and -10 were identified. Monosomy 11, tetraploidies and polyploidies were detected in invasive and poor-differentiated tumors. Hybridization on frozen sections offers another means of analysing surgical samples. FISH to vesical washings can be applied to monitor tumor progression. Hybridizations on paraffine sections and on tissues previously stored in liquid nitrogen allow retrospective studies of the archived materials. Our data suggest that the interphase FISH can become a powerful tool for cytogenetic studies of bladder cancer.

Carcinoma, Transitional Cell↗

Rapid identification of marker chromosomes by in situ hybridization under different stringency conditions.

Six metacentric non-satellite chromosome markers and 4 satellite markers of unknown origin were discovered by routine cytogenetic analysis. These markers were then investigated by isotopic and nonisotopic (FISH) in situ hybridization. In order to determine the origin of small marker chromosomes, a special protocol involving sequential application of defined alphoid and 'classical' satellite DNA probes with chromosome specificity was used. In situ hybridization under low stringency conditions has been performed with DNA probes specific for 4 groups of chromosomes. After preliminary analysis and determination of the possible origin of these marker chromosomes, DNA probes with high chromosome specificity were used under high stringency conditions. Marker chromosomes were found to be derivatives of chromosomes 7, 9 (3 cases), 13, 14 or 22, 21 (2 cases), X and Y.

Chromosomes, Human↗

Karyotype and FISH analysis of a newly established cell line derived from a human bladder carcinoma.

A new human malignant urologic cell line was established in vitro from a moderately differentiated transitional cell carcinoma of the bladder and cytogenetically characterized. Repeated chromosome analyses of the cell line using conventional RHG and GTG banding and non-radioactive in situ hybridization showed a stable karyotype with a modal number of 48 and chromosomal rearrangements, some of which have not been previously described. Numerical deviation included three trisomies (+7, +8, +9) and one nullisomy (-19, -19). Structural changes involved a balanced translocation (1;5)(q12;q12), an isochromosome 3q, a 14p+, and two markers. Fluorescence in situ hybridization (FISH), using biotin-labeled alpha satellite probes for chromosome 9 or painting for chromosomes 1 and 8, applied to interphase nuclei or metaphases showed similar results to those found by conventional cytogenetic study. This cell line may be an interesting model for fuller characterization by molecular biology studies and for testing anti-cancer drugs in vitro.

Aged↗

Assessment of polyploidy in human morulae and blastocysts using co-culture and fluorescent in-situ hybridization.

Fluorescence in-situ hybridization with DNA probes for X, Y and no. 18 chromosomes was used to analyse human morulae (n = 13) and blastocysts (n = 41), obtained after co-culture on Vero cells. On the basis of the number of hybridization signals, the proportion of embryos with more than five polyploid cells was 30.8% for morulae and 29.3% for blastocysts. These values are similar to those for mixoploidy (mosaicism of diploid and polyploid cells) observed in blastocysts of animal species. The results were confirmed by scanning electron microscopy, which showed a wide variation in the size of blastocyst nuclei, and by classical cytogenetic analysis. Mixoploidy seems to be a normal feature in preimplantation embryos and to occur very early in human embryo development. This lays open to doubt the preimplantation diagnosis of genetic errors at these stages, since results obtained from single cell analysis may not be representative of the whole embryo.

Animals↗

[Chromosomal analysis of bladder tumors. Technical aspects, anatomoclinical correlations and perspectives. Report of 18 cases].

The course of bladder tumours is difficult to predict. The most reliable prognostic factor at the present time is histological grade. Cytogenetic subclasses of bladder tumours can be distinguished on the basis of the demonstration of karyotype anomalies in bladder tumour cells. Eighteen patients underwent cytogenetic examination of their bladder tumour and were followed for an average of 35 months. Multivariate analysis of the clinical and laboratory parameters studied revealed the importance of age and the absence of trisomy 7 in the tumour on patient survival. The presence of trisomy 7 in a bladder tumour may therefore constitute a factor of poor prognosis. This hypothesis needs to be confirmed by further studies in larger populations. The search for this anomaly can be performed by fluorescent in situ chromosomal hybridisation, a technique which transforms cytogenetics from an experimental procedure into a routine complementary investigation. These techniques can be performed on urine samples, suggesting the possibility of their application to screening or follow-up of bladder tumours.

Adult↗

Chromosome analysis by image processing in a computerized environment. Clinical applications.

Dealing with a routine regional cytogenetic activity, we have developed and adapted to clinical work a semi automatic karyotyping machine. Attempts for an accurate automated chromosome classification using a neural network have led to partial results. A specific adaptation to cancer cytogenetics is under development (determination of the modal number, translocations analysis with densitometric curves, automatic identification of markers). A specific program allows quantification of chromosome labelling with radioactive probes. Exchanges of digitized karyotypes are feasible with labs using automated karyotyping machines. A local network connects several karyotyping and metaphase finding stations. Guidelines for an international data bank concerning abnormal chromosome images have been elaborated. On the other hand the ISH techniques have been applied to the following topics: identification of human chromosome aberrations in amniotic and chorionic cells, chromosome studies of human gametes and embryos (including sex determination), identification of markers in cancer cells.

Chromosome Aberrations↗

[Complete and homogenous trisomy 9 detected in utero].

During a gestation with oligoamnios and growth retardation noticed at 25th week an amniocentesis allowed us to discover the 14th case of complete trisomy 9, the third detected in utero. It is also the first without heart malformation, otherwise phenotype was usual. The liver had small areas of necrosis with calcifications and slight fibrosis which may be in relation with two cordocentesis made before expulsion. The important phenotype alterations and poor outcome of fetuses with trisomy 9 justify elective abortion.

Abortion, Therapeutic↗

A method for cytogenetic analysis of boar spermatozoa using hamster oocytes.

In this paper, the authors detail a method for displaying boar spermatozoa chromosomes using heterospecific zona-free hamster oocyte penetration technique. Semen samples from two Large-White boars having a normal spermogram were studied. The first one had a normal karyotype (38,XY), the second carried a reciprocal translocation rcp(3;7)(p1,3;q2,1). After in vitro fertilization by capacitated sperm, culture and cytogenetic analysis of hamster eggs we obtained metaphase spreads of spermatozoa chromosomes. The ratio of X- and Y-bearing spermatozoa was 49.2% and 50.8%, respectively.

Animals↗